A struct type defines several elements in a record. The elements of a struct are UNO types with a unique name within the struct. Structs have the disadvantage not to encapsulate data, but the absence of get() and set() methods can help to avoid the overhead of method calls over a UNO bridge. UNO supports single inheritance for struct types. A derived struct recursively inherits all elements of the parent and its parents.

A new feature of OpenOffice.org2.0 is the polymorphic struct type. A polymorphic struct type template is similar to a plain struct type, but it has one or more type parameters, and its members can have these parameters as types. A polymorphic struct type template is not itself a UNO type - it has to be instantiated with actual type arguments to be used as a type.